Bore plug

ABSTRACT

An apparatus and method for plugging a tubular bore is disclosed herein. The apparatus comprises: a shaft member; one or more cylindrical compressible seals slideably disposed around the shaft member, wherein the shaft member passes axially through the one or more cylindrical seals; one or more cylindrical hard sleeves having one or more conical ends slideably disposed around the shaft member and adjacent to the one or more cylindrical seals; a flange attached at or near a distal end of the shaft member, wherein the flange retains the cylindrical sleeves and cylindrical seals on the shaft member; and a pulling mechanism disposed at or near a proximal end of the shaft member, wherein the seal is positioned between the flange and the one or more cylindrical hard sleeves such that compression of the seal causes it to expand away from the shaft member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a non-provisional application of U.S.provisional patent application 61/328,416 filed on Apr. 27, 2010 andentitled “Bore Plug” which is hereby incorporated by reference in itsentirety.

TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to the field of bore plugs, andmore particularly, to an improved bore plug with enhanced lateralcompression.

STATEMENT OF FEDERALLY FUNDED RESEARCH

None.

REFERENCE TO A SEQUENCE LISTING

None.

BACKGROUND OF THE INVENTION

Without limiting the scope of the invention, its background is describedin connection with fluid handling and more particularly, to an improvedapparatus and method for plugging a tubular bore.

After tubing and piping is manufactured, it is often necessary ordesirable to protect the interior of the tubing and piping from theoutside environment. This may especially be true if threads have beenmachined into the interior end surfaces of the tubing or piping.Furthermore, after tubing or piping is installed for its intendedpurpose, it is often necessary to pressure test the system to ensurethat all the piping or tubing is properly joined so that there will beno leaks when the system is placed into service. Additionally, it isoften desired to maintain a positive pressure on the tubes or piping toprevent corrosion or other damage to the interior of the tubes whilethey are being stored or shipped or during construction, such asproviding an internal gas purge during welding.

The prior art teaches many different types of plugs that have beendesigned to plug the ends of the tubular bores of pipes and tubing. U.S.Pat. No. 5,771,937 a device for plugging a pipe includes a resilient,hollow body member that expands with the application of internallyapplied pressure to block the pipe, much like blowing up a ballooninside of a tubular bore. This system requires a source of compressedair or other gas to inflate the balloon.

U.S. Pat. No. 5,119,861 a device is disclosed for plugging a pipe thatcomprises an elastomer seal. The resilient elastomeric seal is attachedto the perimeters of two axially aligned rigid end plates. This devicerelies upon the elasticity of the elastomeric seal to draw the endplates together while radially expanding so as to engage and sealagainst the inner wall of a tubular bore. This device lacks any meansfor tightening the seal beyond the force exerted by the elastomer as theelastomer is allowed to relax from a stretched position.

U.S. Pat. No. 4,968,197 a device is disclosed that includes a disc-likescrew plate, an elastic sealing ring, a horn-like pressure block and alifting eye. The screw plate receives the bottom edge of the sealingring and the horn-like pressure block is mounted on the upper edge. Thescrew plate has a central rod that extends upwardly through a hole inthe pressure block.

The lifting eye is then threaded received on the end of the rod and asthe lifting eye is turned, the block and plate are urged togethercausing the sealing ring to expand against the internal wall of a pipe.

The present inventors had also previously submitted U.S. PatentApplication 20040074549 directed to a Bore Plug, now expired.

SUMMARY OF THE INVENTION

The present invention represents an improvement over the prior BorePlug. The improvements over the prior design include those featuresclaimed herein. The present invention includes An apparatus for plugginga tubular bore, comprising: a shaft member; one or more cylindricalcompressible seals slideably disposed around the shaft member, whereinthe shaft member passes axially through the one or more cylindricalseals; one or more cylindrical hard sleeves having one or more conicalends slideably disposed around the shaft member and adjacent to the oneor more cylindrical seals, wherein the one or more conical ends increasecompression of the seal along the shaft member closer to the shaft; aflange attached at or near a distal end of the shaft member, wherein theflange retains the cylindrical sleeves and cylindrical seals on theshaft member; and a pulling mechanism disposed at or near a proximal endof the shaft member, wherein the seal is positioned between the flangeand the one or more cylindrical hard sleeves such that compression ofthe seal causes it to expand away from the shaft member. In one aspect,the apparatus has two or more cylindrical seals, the cylindrical sealsare separated by at least one of the one or more cylindrical hardsleeves.

In another aspect, the apparatus further comprises: a pressure valve,wherein the shaft member is hollow and wherein the pressure valve issecured within the hollow shaft member at or near the proximal end ofthe shaft member. In another aspect, the pressure valve is securedwithin the hollow shaft by threads and/or by a pneumatic valve having aspring-loaded seal. In one aspect, is brass or metal. In another aspect,cylindrical seals are neoprene, e.g., an elastomer, rubber and/orsynthetic rubber. In yet another aspect, the cylindrical sleeves and theflange are a material selected from the group comprising nylon, brass,aluminum and combinations thereof. The cylindrical sleeves and theflange may be metal. In another aspect, the cylindrical sleeves, theflange and the shaft member are made of different materials or the samematerial. In another aspect, the pulling mechanism comprises a nutdisposed on a threaded outer circumference of the proximal end of theshaft member. In another aspect, the pulling mechanism further comprisesa washer disposed adjacent to a distal end of the nut, wherein thewasher diameter is greater than a diameter of the tubular bore. Inanother aspect, the pulling mechanism causes the hollow shaft member toslide axially in a proximal direction within the one or more cylindricalsleeves and the one or more cylindrical seals.

In another aspect, the bore plug further comprises one or morecompressible sealant holders slideably disposed around the shaft member.In another aspect at least one end of the compressible sealant holder isadjacent to one of the one or more cylindrical sleeves. In anotheraspect, the compressible sealant holder is a spring or a wave spring.Certain examples of diameters for use with the present invention is adifference in a diameter of the one or more cylindrical sleeves and adiameter of the tubular bore is between about 0.02 inches and about 0.2inches. In another aspect, a difference in a diameter of the one or morecylindrical sleeves and a diameter of the tubular bore is between about0.03 inches and about 0.13 inches.

In another embodiment, the present invention includes a method ofplugging a tube, comprising: inserting an expandable plug into a tubularbore, a plug comprising: a shaft member; one or more cylindricalcompressible seals slideably disposed around the shaft member, whereinthe shaft member passes axially through the one or more cylindricalseals; one or more cylindrical hard sleeves having one or more conicalends slideably disposed around the shaft member and adjacent to the oneor more cylindrical seals, wherein the one or more conical ends increasecompression of the seal along the shaft member closer to the shaft; aflange attached at or near a distal end of the shaft member, wherein theflange retains the cylindrical sleeves and cylindrical seals on theshaft member; and a pulling mechanism disposed at or near a proximal endof the shaft member; and compressing the one or more cylindrical seals,wherein the seal is positioned between the flange and the one or morecylindrical hard sleeves such that compression of the seal causes it toexpand away from the shaft member to seal the tubular bore. In oneaspect, the step of compressing the one or more cylindrical sealsfurther comprises: tightening a nut disposed on a threaded outercircumference of a proximal end of the shaft member, wherein the pullingmechanism comprises the nut and wherein the pulling mechanism exerts anaxial force on the shaft member in a proximal direction to compress theone or more cylindrical seals at the conical ends, thereby increasingthe compression along the seal. In another aspect, the method furthercomprises: inserting a sealant into a compressible sealant holder,wherein the sealant holder is slideably disposed around the shaft memberand is adjacent to one of the one or more cylindrical sleeves;compressing the sealant holder during the step of compressing the one ormore cylindrical seals; expelling the sealant from the sealant holder asthe sealant holder compresses. In another aspect, the shaft member ishollow and wherein the expandable plug further comprises a pressurevalve secured within the hollow shaft, the method further comprising:opening the pressure valve before compressing the one or morecylindrical seals; allowing a fluid in the tubular bore to flow throughthe pressure valve while compressing the one or more cylindrical seals.In another aspect, the methods further comprises: determining thepressure within the tubular bore after sealing the tubular bore; andadding additional fluid through the pressure valve to achieve a desiredpressure within the tubular bore. In yet another aspect, the methodfurther comprises: opening the pressure valve; removing fluid throughthe pressure valve to achieve a desired pressure within the tubularbore.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the features and advantages of thepresent invention, reference is now made to the detailed description ofthe invention along with the accompanying figures and in which:

FIGS. 1 and 2 are lateral views of the bore plug of the presentinvention;

FIG. 3 is an exploded view of the components of the bore plug of thepresent invention;

FIGS. 4 and 5 are cross-sectional views of the improved bore plug of thepresent invention, FIG. 4 shows the bore plug before engagement and FIG.5 shows the compression after engagement of the bore plug at the pointof compression;

FIGS. 6 and 7 are cross-sectional views of an alternative improved boreplug of the present invention, FIG. 6 shows the bore plug beforeengagement and FIG. 7 shows the compression after engagement of the boreplug at the point of compression; and

FIGS. 8 and 9 are cross-sectional views of an another alternativeimproved bore plug of the present invention, FIG. 8 shows the bore plugbefore engagement and FIG. 9 shows the compressions after engagement ofthe bore plug at the point of compression.

DETAILED DESCRIPTION OF THE INVENTION

While the making and using of various embodiments of the presentinvention are discussed in detail below, it should be appreciated thatthe present invention provides many applicable inventive concepts thatcan be embodied in a wide variety of specific contexts. The specificembodiments discussed herein are merely illustrative of specific ways tomake and use the invention and do not delimit the scope of theinvention.

To facilitate the understanding of this invention, a number of terms aredefined below. Terms defined herein have meanings as commonly understoodby a person of ordinary skill in the areas relevant to the presentinvention. Terms such as “a”, “an” and “the” are not intended to referto only a singular entity, but include the general class of which aspecific example may be used for illustration. The terminology herein isused to describe specific embodiments of the invention, but their usagedoes not delimit the invention, except as outlined in the claims.

The term “plug” or “plug fitting” broadly encompasses any type offitting or connection which may be frictionally held in a hole.

The term “shaft” as used herein refers to any elongated threaded bodysuch as a bolt or shaft, as well as a spindle. The terms “axial” and“axially” used herein refer to a direction generally parallel to theaxis of a shaft.

The term “bore” as used herein refers to an open projection having acircular cross-section. The term “flange” as used herein is generallyunderstood as a separable connecting element.

As used herein the term “sealant” is intended to include any adhesivematerial which is used for filling voids and interstices to provide aseal against moisture, dust, solvents and/or other fluids.

The term “threads” as used herein includes grooves and other structureswherein overlapping interengaging surfaces hold an element against axialseparation.

The term “pressure valve” as used herein, refers a device for one ormore of controlling, regulating, adjusting, maintaining, and releasingpressure.

In describing the present invention, the term “distal end” is usedherein to refer to the end closest to the normally exposed shaft member.The term “proximal end” is used herein to refer to the end farthest fromthe normally exposed shaft member.

The term “brass” or “brass alloy” as used herein denotes an alloywherein the principal constituents are copper and zinc. Brass alloyswhich may be employed include not only binary alloys, but also ternaryalloys, such alloys containing additional incidental ingredients such asnickel and tin present in minor amounts.

As used herein the term “washer” is intended to encompass any tubularmember which is subjected to axial forces. The term “spring” as usedherein refers to an elastic body that recovers its original shape whenreleased after being distorted. A spring behaves in accordance withHooke's Law in that it will undergo substantial distortion within itselastic limit and thereafter recover its original shape. The term is notintended to connote the infinitesimal distortion which is detectable ina normally rigid body when subjected to great stress.

As used herein the term “circumference” is intended to signify an inneror outer edge of an object in one plane, and is not limited to acircular shape. As used herein the term “diameter” is defined to includethe conventional definition of a line across a circular cross-sectionthrough the center of that cross-section. In some instances, theelements described herein as having a diameter may be non-circular. Inthose instances, the term “diameter” refers to a line across thenon-circular cross-section, in most instances through a center point ofthe non-circular cross-section.

One problem with the existing tubular bore plugs is that they provide noway for pressurizing the tubular bore after a plug is installed or forchecking whether a tubular bore is under a positive pressure after thetubular bore plug has been installed. Without first installing anadditional valve on the tube or pipe, the prior art devices do notprovide a way for maintaining a positive pressure within a sealedtubular bore or provide ways for increasing or decreasing the pressure.

Another problem that existing tubular bore plugs cannot solve isinstalling a bore plug when there is a flow of fluid coming out of thetubing or piping. The prior art bore plugs may be installed properlyonly when the pipe is completely out of service. What is needed is atubular bore plug that may be installed when there is a fluid flow inthe tubular bore and further provides a means for pressuring ormaintaining a positive pressure within the tubular bore after the boreplug has been installed.

The present inventors have overcome the problems with prior art boreplugs by providing for conical compression fittings that increase thelateral compression about the shaft member toward the inside portion ofthe tubing that is engaged by the sleeves having the conical ends.

The hollow shaft member providing an axis for the expandable plug mayhave any diameter and length suitable for plugging a tubular bore. Thehollow shaft member may take any form, but the shaft member iscylindrical. Advantageously, the hollow shaft member with the pressurevalve may be a standard valve as used on a truck or automobile tire. Thestandard valve used on tires includes the valve stem, which is a hollowtube, and the valve core, often called a Schrader valve, which isinserted into the valve stem. These standard valves are available fromSchrader-Bridgeport, a Delaware corporation. Furthermore, valves havinga standard bore core chamber No. 1 as defined by the Tire and RimAssociation, are available in varying lengths, from about 2 inches toabout 6 inches, and have a standard ID of about 0.21 inches and astandard OD of about 0.31 inches. Other standard sizes are alsoavailable, such as standard bore core chamber No. 2 and standard borechamber No. 3, also as defined by the Tire and Rim Association. If aparticular tubular bore plugging application requires a plug lengthdifferent than the standard lengths available for tire valves, thestandard valve stems may be lengthened or shortened by cutting or byadding additional stem material by means well known to those havingordinary skill in the art.

The standard truck and automobile tire valves are often rated for amaximum working pressure of about 300 psig but the spring loadedpressure valves are available for much higher working pressures ifrequired for a particular bore plugging application. The bore plug ofthe present invention has successfully maintained pressures on tubularbores up to about 500 psig. Typically, however, the normal applicationis 25 psig or less, in particular, those application for use with verylong tube lengths, e.g., 1,000, 2,500, 5,000, 10,000, 20,000, 30,000,40,000 or even 50,000 feet in length. In addition to being used fortires, the pneumatic type valves having a spring-loaded seal asdiscussed above are also used conventionally by many other industries,such as the refrigeration and air conditioning industry. The hollowshaft member is made of a metal and more is made of brass, aluminum,copper or a combination thereof.

The flange on the second end of the hollow shaft member may comprise oneor more ribs, a plate or other form secured to the hollow shaft membersuitable for retaining the cylindrical seals and sleeves on the hollowshaft. The flange is of the same material as the hollow shaft member andis a metal, for example, brass, aluminum, copper or a combinationthereof.

The cylindrical seals, through which the hollow shaft member passes asan axis, are made from a resilient pliable material that is suitable forforming a seal when expanded against the inner surface of the tubularbore. The cylindrical seals are made of a thermoplastic, e.g., thecylindrical seals may made of an elastomer. Alternatively, thecylindrical seals may be made of, e.g., synthetic or natural rubber,composite materials, black nylon. Neoprene is one material for thecylindrical seals but other elastomers may be superior for plugging atubular bore containing corrosive or other difficult to handlematerials. Selection of all materials used in the present invention maybe made based upon the plugging application as known to those havingordinary skill in the art. An advantage of providing cylindrical sealsmade of a resilient, pliable material is that a tight seal may be formedeven in a tubular bore having imperfections or threads because the sealmaterial fills voids, such as threads or pits, and molds itself aroundprotrusions, such as a tube seam.

The cylindrical sleeves through which the hollow shaft member passes asan axis are made of a metal. The sleeves are made from brass, aluminum,copper or a combination thereof. The sleeves may be bushings and aremade from a material that is sufficiently strong to transfer compressiveforces to the cylindrical seals, thereby making the seals expand againstthe inner wall of the tubular bore to create the seal. It should benoted that the hollow shaft member, the flange, the pulling mechanismand the cylindrical sleeves may all be made of the same material orindividual components may be made of different materials or combinationsof materials.

The expandable plug of the present invention may be used to plugcylindrical bores having a wide range of diameters. The diameter of theexpandable bore is varied by changing the diameters of the cylindricalseals and cylindrical sleeves. The clearance between the unexpanded plugand the interior walls of the tubular bore is typically less for a smalldiameter tubular bore than for a large diameter tubular bore becausethere is less volume of elastomer making up the cylindrical seals in thesmaller diameter expandable plug. For example, for tubular bores havingan inner diameter (ID) of less than 0.5 inches, one clearance is about0.0625 inches. For tubular bores having an ID of about 1 inch, anotherclearance is about 0.125 inches. Generally, the clearance between thesides of the plug and the ID of the tubular bore may be between about0.02 inches and about 0.2 inches. The clearance between the sides of theplug and the ID of the tubular bore may be between about 0.03 inches andabout 0.13 inches.

The arrangement and number of the cylindrical seals and the cylindricalsleeves may vary as long as the arrangement provides for the cylindricalseals to be compressed between the pulling mechanism and the flange. Inone embodiment, two separate cylindrical seals are used to facilitateuniform circumferential fitting of the expandable plug into the tubularbore. Furthermore, the use of two cylindrical seals helps prevent theexpandable plug from becoming cocked at an angle either during or aftersealing the tubular bore with the expandable plug. Furthermore, theability for the bore plug to be self-aligning and to remain alignedwithin the tubular bore increases with increasing length of thecylindrical seals. In one embodiment, though not required, thecylindrical seal is compressed between two cylindrical sleeves ratherthan one cylindrical sleeve and the flange.

As noted above, a flange and a pulling mechanism are provided atopposite ends of the hollow shaft member of the compressible plug. As anaxial force is exerted by the pulling mechanism upon the hollow shaftmember, the resulting compressive forces compress the cylindrical sealscausing them to radially expand, thereby creating the seal in thetubular bore. In one embodiment, two cylindrical seals and threecylindrical sleeves are arranged on the hollow shaft member in thefollowing order, starting at the distal end: flange, first sleeve, firstseal, second sleeve, second seal, third sleeve, and pulling mechanism.In this arrangement, the first and second sleeves exert compressiveforces on the first cylindrical seal and the second and third sleevesexert compressive forces on the second cylindrical seal. Alternatively,the flange may replace one of the sleeves, providing an arrangement asfollows: flange, first seal, first sleeve, second seal, second sleeve,and pulling mechanism. As one having ordinary skill in the art willrecognize, there are many different arrangements and numbers ofcylindrical seals and cylindrical sleeves that may be placed on thehollow shaft member in accordance with the present invention.Optionally, sleeves and seals may also be placed adjacent to each otheras long as the compressive forces may be exerted against the seals toforce the seals to expand radially.

The pulling mechanism is a device that applies an axial force to thehollow shaft member, thereby causing the hollow shaft member to slide ina proximal direction through the axial openings of the cylindrical sealsand cylindrical sleeves through which the hollow shaft member passes.The pulling mechanism further prevents the cylindrical seals andcylindrical sleeves from being pulled from the tubular bore, therebyexerting compressive forces on the cylindrical seals. The pullingmechanism may be a pulley device through which forces exerted on a wirerunning through the pulley and attached to the hollow shaft memberexerts axial forces upon the hollow shaft member. Alternatively, thehollow shaft member may comprise teeth that engage a pawl to form aratchet mechanism similar to that found in a standard caulking gun.

In one embodiment, the pulling mechanism comprises a nut that is screwedonto a threaded portion of the hollow shaft member and a washer that hasa diameter greater than the diameter of the tubular bore. The washer islocated adjacent to the nut on a distal end of the nut. To create theseal in the tubular bore, the expandable plug is placed into the tubularbore and the washer is held against the opening of the tubular bore. Asthe nut is tightened, an axial force is applied to the hollow shaftmember causing the hollow shaft member to slide in a proximal directionthrough the axial openings of the cylindrical seals and cylindricalsleeves, thereby placing the seals in compression between the flange andthe washer. As the nut continues to be tightened, greater compressiveforces are generated, causing the cylindrical seals to expand radiallyagainst the interior wall of the tubular bore, thereby creating a seal.Typically, two to four turns of the nut are sufficient to create enoughcompressive force on the cylindrical seals to create the seal for thetubular bore. However, for a given application and expandable plug, afewer number or greater number of turns may be required.

A special tool may be used to hold the washer of the pulling mechanismagainst the tubular bore opening while tightening the nut. The toolcomprises a handle for gripping the tool and a threaded port in thehandle. The hollow shaft member is threaded on the outer surface of theproximal end so that the hollow shaft member may be secured in thethreaded port of the handle. A stationary pin in the center of thethreaded port depresses the plunger pin of the pressure valve locatedwithin the hollow shaft member as the hollow shaft member is secured tothe handle. Advantageously, if there is a flow of fluid through thetubular bore while the expandable seal is being inserted, the fluid canflow through the open pressure valve and through the handle, therebyventing through a second port on the handle. Optionally, a hose may beconnected to the second port to direct the flow away from the user.After the cylindrical seals have radially expanded to create the seal,the special tool may be removed, causing the pressure valve to close asthe plunger pin on the pressure valve is released.

To remove the expandable plug from the tubular bore, the procedure maybe reversed. The axial force on the hollow shaft member is removed,thereby removing the compressive forces being applied on the cylindricalseals. With the compressive forces removed, the cylindrical sealscontract radially so that the expandable plug may be removed from thecylindrical bore. If the expandable seal has been installed for a periodlong enough for the cylindrical seals to have lost some of theirresilience, the force required to pull the expandable plug is increased.Temporary installations of the expandable plugs of the present inventionshould be replaced after a set period that may be determined by factorsdependant on an individual plugging applications, such as temperature,pressure, vibration, expansion, contraction, corrosive conditions andother factors known to those having ordinary skill in the art.Typically, the expandable plugs are not reusable without at least firstproviding new cylindrical seals but there are tubular bore pluggingapplications where re-use would be acceptable.

The pressure valve contained within the hollow shaft member of anembodiment provides advantages over conventional tubular bore plugs. Thepressure valve allows a positive pressure of air or an inert gas to beachieved within the plugged tubular bore. Because a pressure valve isthe readily available tire valve, a conventional tire pressure gauge maybe used to easily measure the positive pressure within the tubular bore.If the pressure is too low, compressed air or another gas may beinjected through the tire valve to raise the pressure within the sealedtubular bore, thereby protecting the walls of the tubular bore fromcorrosion or other damage resulting from exposure to the outerenvironment. Furthermore, the pressure may similarly be checked beforeremoving the plug from the tubular bore, thereby providing increasedsafety to a user by providing a means to check the pressure and relieveany pressure before the user removes the expandable plug. Alternatively,if monitoring pressure within the tubular bore or injecting additionalgas or other fluid is not desired, the expandable plug of the presentinvention may be practiced without the pressure valve and the hollowshaft member may be replaced with either a solid shaft member or acapped hollow shaft member. The present invention may be practiced inall other aspects that do not involve the internal pressure valveregardless of whether the shaft member is hollow or solid. Therefore, ifthe functions of the pressure valve are not required, the invention maybe practiced without the pressure valve and with a solid or capped shaftmember.

Another embodiment of the present invention provides an expandable sealfor plugging a tubular bore permanently. In this embodiment, one or morecompressible sealant holders are slideably disposed upon the hollowshaft member. In one embodiment, the sealant holder is a coiled spring.A sealant holder may be used that is a wave spring because the wavespring provides a higher volume, for a given spring length, between thecoils prior to compression. A sealant may be a sealing epoxy, readilyavailable in both one and two component forms and well known to thosehaving ordinary skill in the art. Prior to inserting the expandable pluginto the tubular bore, the sealing epoxy is packed between the coils ofthe spring disposed upon the hollow shaft member. Then, as the pullingmechanism exerts axial forces upon the hollow shaft member to compressthe cylindrical seals, the spring is also compressed, forcing thesealing epoxy out from between the coils and into the void areas betweenthe expandable plug and the tubular bore. The sealing epoxy is packedinto the void areas creating a permanent seal.

FIGS. 1 and 2 are side views of the bore plug apparatus 10, thatincludes a shaft member 12 with nut 14 around threads on the shaftmember 12 (generally hollow). A generally cylindrical compressible seal16 surrounds the shaft member 12 and is positioned between a internalflange 18 and one or more cylindrical hard sleeves 20 that arepositioned, in these figures, on either side of the cylindricalcompressible seal 16. An external flange 22 is shown that prevents thebore plug from completely entering a tube, thereby serving the dualpurpose of acting as a compression flange and to prevent the bore plugfrom going into the tube.

FIG. 3 is an exploded view of the bore plug apparatus 10, that includesa shaft member 12 with nut 14 around threads on the shaft member 12. Agenerally cylindrical compressible seal 16 surrounds the shaft member 12and is positioned between a flange 18 and one or more cylindrical hardsleeves 20 that are positioned, in these figures, on either side of thecylindrical compressible seal 16. A washer 24 is depicted to bepositioned between external flange 22 and nut 14. Finally, in certainembodiments in which air or other internal pressure is used to causecompression of the cylindrical compressible seal 16, a spring-loaded,pin activated pressure valve 26 is depicted.

If there is a flow of gas through the shaft member 12 while the boreplug 10 is being installed, then the pressure valve 26 is open while thecylindrical compressible seals 16 are being compressed. By allowing gasto flow through the pressure valve 26 during the compression of thecylindrical seals, a good seal may be achieved when there is a flow ofgas or other fluid through the shaft member 12. Nut 14 exerts an axialforce on the shaft member 12 and can be used to partially compress theone or more cylindrical hard sleeves 20, the cylindrical compressibleseal 16 against internal flange 18 and external flange 22, while notexpanding the cylindrical compressible seal 16 to an outer diametergreater than the internal diameter of a tube that is intended to beplugged.

The present invention is best described with the following figures.FIGS. 4 and 5 are cross-sectional views of the improved bore plug 10 ofthe present invention. FIG. 4 shows the bore plug 10 before engagementof the cylindrical compressible seals 16, which includes a clearance 30between a tube 28 and the bore plug apparatus 10.

FIG. 5 shows the compression after engagement of the bore plug 10 at thepoint of compression 32 caused by the conical portion 34 of thecylindrical hard sleeve 20. The cylindrical compressible seal 16 expandsto close the clearance 30 at the specific point along the cylindricalcompressible seal 16 that greatly enhances the strength of the fit orengagement of the bore plug 10 in the tube 28.

FIGS. 6 and 7 are cross-sectional views of an alternative improved boreplug of the present invention. FIG. 6 shows the bore plug 10 beforeengagement of the cylindrical compressible seals 16, which includes aclearance 30 between a tube 28 and the bore plug apparatus 10.

FIG. 7 shows the compression after engagement of the bore plug 10 at thepoint of compression 32 caused by the conical portion 34 of thecylindrical hard sleeve 20. The conical portion 34 of the cylindricalhard sleeve 20 is angled from 5 to about 15 degrees, and will most oftenus an angle of 5, 6, 7, 9, 10, 11, 12, 13, 14, or 15 degrees from theradial cross-section. The cylindrical compressible seal 16 expands toclose the clearance 30 at the specific point along the cylindricalcompressible seal 16 that greatly enhances the strength of the fit orengagement of the bore plug 10 in the tube 28.

FIGS. 8 and 9 are cross-sectional views of an another alternativeimproved bore plug of the present invention, FIG. 8 shows the bore plug10 before engagement and FIG. 9 shows the compressions after engagementof the bore plug at two points of compression 32.

It is contemplated that any embodiment discussed in this specificationcan be implemented with respect to any method, kit, reagent, orcomposition of the invention, and vice versa. Furthermore, compositionsof the invention can be used to achieve methods of the invention.

It will be understood that particular embodiments described herein areshown by way of illustration and not as limitations of the invention.The principal features of this invention can be employed in variousembodiments without departing from the scope of the invention. Thoseskilled in the art will recognize, or be able to ascertain using no morethan routine experimentation, numerous equivalents to the specificprocedures described herein. Such equivalents are considered to bewithin the scope of this invention and are covered by the claims.

All publications and patent applications mentioned in the specificationare indicative of the level of skill of those skilled in the art towhich this invention pertains. All publications and patent applicationsare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

The use of the word “a” or “an” when used in conjunction with the term“comprising” in the claims and/or the specification may mean “one,” butit is also consistent with the meaning of “one or more,” “at least one,”and “one or more than one.” The use of the term “or” in the claims isused to mean “and/or” unless explicitly indicated to refer toalternatives only or the alternatives are mutually exclusive, althoughthe disclosure supports a definition that refers to only alternativesand “and/or.” Throughout this application, the term “about” is used toindicate that a value includes the inherent variation of error for thedevice, the method being employed to determine the value, or thevariation that exists among the study subjects.

As used in this specification and claim(s), the words “comprising” (andany form of comprising, such as “comprise” and “comprises”), “having”(and any form of having, such as “have” and “has”), “including” (and anyform of including, such as “includes” and “include”) or “containing”(and any form of containing, such as “contains” and “contain”) areinclusive or open-ended and do not exclude additional, unrecitedelements or method steps.

The term “or combinations thereof” as used herein refers to allpermutations and combinations of the listed items preceding the term.For example, “A, B, C, or combinations thereof” is intended to includeat least one of: A, B, C, AB, AC, BC, or ABC, and if order is importantin a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB.Continuing with this example, expressly included are combinations thatcontain repeats of one or more item or term, such as BB, AAA, MB, BBC,AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan willunderstand that typically there is no limit on the number of items orterms in any combination, unless otherwise apparent from the context.

As used herein, words of approximation such as, without limitation,“about”, “substantial” or “substantially” refers to a condition thatwhen so modified is understood to not necessarily be absolute or perfectbut would be considered close enough to those of ordinary skill in theart to warrant designating the condition as being present. The extent towhich the description may vary will depend on how great a change can beinstituted and still have one of ordinary skilled in the art recognizethe modified feature as still having the required characteristics andcapabilities of the unmodified feature. In general, but subject to thepreceding discussion, a numerical value herein that is modified by aword of approximation such as “about” may vary from the stated value byat least ±1, 2, 3, 4, 5, 6, 7, 10, 12 or 15%.

All of the compositions and/or methods disclosed and claimed herein canbe made and executed without undue experimentation in light of thepresent disclosure. While the compositions and methods of this inventionhave been described in terms of preferred embodiments, it will beapparent to those of skill in the art that variations may be applied tothe compositions and/or methods and in the steps or in the sequence ofsteps of the method described herein without departing from the concept,spirit and scope of the invention. All such similar substitutes andmodifications apparent to those skilled in the art are deemed to bewithin the spirit, scope and concept of the invention as defined by theappended claims.

REFERENCES

-   U.S. Pat. No. 5,119,861: Fail Safe Pipe Plug.-   U.S. Pat. No. 4,968,197: Blank Duct Plug.

What is claimed is:
 1. An apparatus for plugging a tubular bore,comprising: a shaft member; one or more cylindrical compressible sealsslideably disposed around the shaft member, wherein the shaft memberpasses axially through the one or more cylindrical seals; one or morecylindrical sleeves having one or more conical ends slideably disposedaround the shaft member and adjacent to the one or more cylindricalseals, wherein the one or more conical ends increase compression of theseal along the shaft member closer to the shaft; a flange attached at ornear a distal end of the shaft member, wherein the flange retains thecylindrical sleeves and cylindrical seals on the shaft member; and apulling mechanism disposed at or near a proximal end of the shaftmember, wherein the seal is positioned between the flange and the one ormore cylindrical hard sleeves such that compression of the seal causesit to expand away from the shaft member.
 2. The apparatus of claim 1,wherein the apparatus has two or more cylindrical seals, the cylindricalseals are separated by at least one of the one or more cylindricalsleeves.
 3. The apparatus of claim 1, further comprising: a pressurevalve, wherein the shaft member is hollow and wherein the pressure valveis secured within the hollow shaft member at or near the proximal end ofthe shaft member.
 4. The apparatus of claim 3, wherein the pressurevalve is secured within the hollow shaft by threads.
 5. The apparatus ofclaim 3, wherein the pressure valve is a pneumatic valve having aspring-loaded seal.
 6. The apparatus of claim 1, wherein the shaftmember is brass.
 7. The apparatus of claim 1, wherein the shaft memberis a metal.
 8. The apparatus of claim 1, wherein the cylindrical sealsare neoprene.
 9. The apparatus of claim 1, wherein the cylindrical sealsare a material selected from the group comprising an elastomer, rubberand synthetic rubber.
 10. The apparatus of claim 1, wherein thecylindrical sleeves and the flange are a material selected from thegroup comprising nylon, brass, aluminum and combinations thereof. 11.The apparatus of claim 1, wherein the cylindrical sleeves and the flangeare metal.
 12. The apparatus of claim 1, wherein the cylindricalsleeves, the flange and the shaft member are made of differentmaterials.
 13. The apparatus of claim 1, wherein the pulling mechanismcomprises a nut disposed on a threaded outer circumference of theproximal end of the shaft member.
 14. The apparatus of claim 13, whereinthe pulling mechanism further comprises a washer disposed adjacent to adistal end of the nut, wherein the washer diameter is greater than adiameter of the tubular bore.
 15. The apparatus of claim 1, wherein thepulling mechanism causes the hollow shaft member to slide axially in aproximal direction within the one or more cylindrical sleeves and theone or more cylindrical seals.
 16. The apparatus of claim 1, furthercomprising: one or more compressible sealant holders slideably disposedaround the shaft member.
 17. The apparatus of claim 16, wherein at leastone end of the compressible sealant holder is adjacent to one of the oneor more cylindrical sleeves.
 18. The apparatus of claim 16, wherein thecompressible sealant holder is a spring.
 19. The apparatus of claim 1,wherein a difference in a diameter of the one or more cylindricalsleeves and a diameter of the tubular bore is between about 0.02 inchesand about 0.2 inches.
 20. The apparatus of claim 1, wherein a differencein a diameter of the one or more cylindrical sleeves and a diameter ofthe tubular bore is between about 0.03 inches and about 0.13 inches.